MISS PIGGY STARS IN 'GREAT MUPPET CAPER'

AFTER decades of doing without, moviegoers have a team of stars on which to heap the adoration they once dumped on Nelson Eddy and Jeanette MacDonald. All hail Kermit the Frog and Miss Piggy! They've been around for a while, but their romantic possibilities are the revelation of ''The Great Muppet Caper,'' the new, sometimes riotously unruly Muppet movie that opens today at the Ziegfeld Theater.

Here is a thoroughly genial movie, a combination of A.A. Milne, Busby Berkeley and a small bit of Blake Edwards, in which Kermit, Miss Piggy, Fozzie Bear and the other Jim Henson-Frank Oz puppets become involved with Diana Rigg, Charles Grodin and a number of guest stars in a not quite all-singing, all-dancing romantic melodrama about jewel thievery in the London of haute couture, great town houses and hotels where the bellboys are uniformed mice.

Kermit the Frog is not as resolutely expressionless as Mr. Eddy was, and he doesn't sing with the nasal force that so distinguished Mr. Eddy's ''Stout-Hearted Men,'' and he's a good deal shorter, but he's a match for Mr. Eddy where it counts. Kermit has heart, and within his eye, there's enough beauty to transform Miss Piggy into Miss MacDonald whenever he beholds her.

Miss Piggy would probably resent being compared to Miss MacDonald. She obviously considers her je ne sais quoi unique, which it is. She also possesses a curious but most winning lack of self-awareness, the kind you sometimes see in miniature poodles that behave as if they were Great Danes.

Miss Piggy, shaped like one of those wooden-ribbed water tanks that are particular to New York roofs, comes on as the svelte beauty she knows herself to be, which is not unlike Miss MacDonald who, at 30, played an innocent teen-ager in ''Naughty Marietta.'' What's more, Miss Piggy, when required, can tap dance like Ruby Keeler and lead a water ballet in the manner of an extremely tubby Esther Williams. She's Jeanette MacDonald with all sorts of extra features at no extra cost.

''The Great Muppet Caper,'' directed by Mr. Henson, begins in New York, where Kermit and Fozzie Bear, a reporter-photographer team, are soon dismissed by their newspaper editor for outright incompetence. While the famous fashion designer Lady Holiday (Miss Rigg) is being noisily robbed of a fortune in jewels on one side of the street, Kermit and Fozzie, on the other side, have been too busy photographing a chicken to notice the page 1 story taking place.

The movie cuts to London, where Kermit and Fozzie have flown to recoup their reputations by solving the jewel heist. It's there that Kermit meets and falls immediately, profoundly in love with Miss Piggy, whose aim in life is to become one of the famous ''Holiday models.''

For the most part, ''The Great Muppet Caper'' keeps its whimsy well disciplined. There's a superfunny sequence in which John Cleese (of the Monty Python crew) plays a very proper upper-class Englishman who refuses to find anything unusual in the sight of a pig climbing up the side of his house.

An error has occurred. Please try again later.

You are already subscribed to this email.

In the kind of nightclub sequence that was obligatory in certain movies of the 30's, there's a smashing production number starring Miss Piggy as the object of the attention of several dozen chorus boys dressed in white tie and tails. It's not telling too much to report that she even gets her chance to become the top Holiday model by going on as a last-minute replacement at the premiere showing of the Holiday collection.

The caper part of the plot, written with good humor by a gang of four, has something to do with attempts to steal what's called the ''fabulous Baseball Diamond,'' a diamond the size of a big league hardball, from Lady Holiday and to pin the crime on the unfortunate Miss Piggy.

The movie contains several more cheery, Disneyesque songs than are necessary, but they are made tolerable by the presence of Kermit and Miss Piggy and by a lot of dialogue that recalls the Milne ''Pooh'' stories. Says Fozzie Bear as he and two companions are sailing aloft in a hot-air balloon, ''I wonder how far one can plummet before one touches down.'' Not quite A.A. Milne but still funny is a running gag in which one Muppet, advised by another Muppet to catch the thieves redhanded, asks, ''What color are their hands now?''

In addition to Miss Rigg, Mr. Grodin and Mr. Cleese, the other live people who turn up in the movie include Peter Ustinov, Robert Morley and Jack Warden. The real stars are Kermit and Miss Piggy, one of whose nicest traits is the gracious way she acknowledges compliments that sometimes haven't been given. It's the confident expectation that they will be given that saves this essentially vulnerable pig in situations that would embarrass a star of lesser stature. What about starring Kermit and Miss Piggy in a remake of ''Rose Marie''?

A Couple to Adore

THE GREAT MUPPET CAPER, directed by Jim Hen- son; written by Tom Patchett, Jay Tarses, Jerry Juhl and Jack Rose; director of photography, Oswald Morris; edited by Ralph Kemplen; music and lyrics by Joe Raposo; produced by David Lazer and Frank Oz; released by Universal Pictures. At the Ziegfeld, the Avenue of the Americas and West 54th Street. Running time: 95 minutes. This film is rated G.